Thanks for posting this very clear picture. A ruler next to the specimen would have shown how big it is, but even without a measure of scale I can tell it's a cow jaw bone. Cow jaw bones have this curved shape on the lower edge you don't see in horses or sheep. Please compare cow, horse and sheep skulls and jaw bones following these links.

The camel skull looks very different. Here is a photo of a dromedary skull. Cows have three molars and three premolars on the mandible (lower jaw), and the incisives in front. Nothing in between. Camels have visible canines between incisives and the P2 premolar, which itself is way forward and there is a large gap between it and the P3 premolar.